New in buildbot 0.8.4 is support for tracking various performance metrics inside the buildbot master process. Currently these are logged periodically according to the log_interval configuration setting of the Metrics Options configuration.
If Web Status is enabled, the metrics data is also available via /json/metrics.
The metrics subsystem is implemented in buildbot.process.metrics. It makes use of twisted's logging system to pass metrics data from all over buildbot's code to a central MetricsLogObserver object, which is available at BuildMaster.metrics or via Status.getMetrics().